Microsonic acoustic wave devices employ materials having acousto-electric properties wherein high frequency acousttic waves are generated by applying electric potentials. Low loss broadband acoustic delay lines, for example, comprise single crystal wafers of lithium niobate having conductive elements deposited thereon. The surface of the lithium niobate crystal, after polishing to the desired thickness, which can be on the order of less than about one micron, is metallized so as to be able to bond a wire onto the lithium niobate crystal by a room temperature, ultrasonic bonding process. The metal film on the lithium niobate must be strongly adherent to the lithium niobate crystal to avoid delamination during and after the ultrasonic bonding step. Conventional adherent metal layers, such as chromium, titanium, tantalum and the like, have proven to be inadequately adherent to lithium niobate crystals. A conventional chromium-gold layer on a lithium niobate crystal completely delaminated when subjected to an ultrasonic bonding step. Thus in order to make practicable acoustic devices using lithium niobate, an adherent bonding metal has been sought.